The present invention relates to a process for the production of a fiber web on a movable, gas-permeable surface of a continuous laydown belt which is under vacuum and which forms a distribution chamber. After the fibers are mechanically opened, the fiber flow is conducted into the distribution chamber by means of an air current and additional air currents are delivered to the distribution chamber.
German Preliminary Published Application 2 149 892 discloses a process of the above mentioned type for the production of fiber webs in which dry fibers are deposited on a gas permeable laydown belt which closes off a distribution chamber in downward direction. In this case, additional air currents are introduced into the distribution chamber to deflect the flow charged with fibers. These additional air currents are employed to prevent an uncontrollable fiber laydown in such a way that the fiber-charged vertical gas flow, when the distribution chamber is centered and in further travel in the direction of the laydown belt, follows a path similar to a ballistic curve or trajectory. This provides a separation of the incoming fibers according to their size in such a way that the coarser and heavier fibers are pushed farther out while the finer and lighter fibers are laid down via the shortest path to the laydown belt. This type of process makes an opening of the fibers impossible since, as a result of the different direction air currents, an agglomeraton of larger fiber particles or a clinging of smaller fiber particles to larger fiber particles is possible. When these bundles of fibrous lignocellulose particles are laid down in the web, a non-uniform web is obtained which in further processing to board-like articles leads to waste with respect to strength and density.